"Club drugs," a relatively new category of illicit drugs that includes ketamine, MDMA (ecstasy), GHB, and methamphetamine, have become increasingly common across a variety of subpopulations. Ketamine hydrochloride (informally known as "Special K," "Vitamin K," "ketamine," or simply "K") is a congener of phencyclidine (PCP) that produces both psychological effects, such as hallucinations and depression, and physiological responses, like raised blood pressure and impaired motor functions. Recently collected pilot data indicates that ketamine is being intravenously injected among high-risk youth in New York City. However, the practices employed in the preparation and injection of ketamine has yet to be systematically described. Furthermore, since the effects of these practices on risk for viral transmission are unknown, formative research is needed. In previous research, we developed an ethnographic methodology using direct ethnographic observation to build a descriptive typology of heroin injection practices, and are currently applying this methodology to describe crack cocaine injection. In this application, we propose to extend our methodology to illustrate the emergence of ketamine injection among high-risk youth. We will describe the physical settings and injection groups in which ketamine injection practices are common among high risk youth; compare and contrast antecedent factors associated with initiating use of ketamine among high risk youth; and describe the unintended physical, psychological, and cognitive consequences associated with ketamine injection among high risk youth. Data from interviews with ketamine injectors and direct observation of ketamine injections will be analyzed and will lead to the development of a cogent descriptive typology of ketamine injection practices. Furthermore, ethnographic data will be used to model the effects of ketamine preparation and practices on the transmissibility of HIV-1.